1. System for the Analysis and Design for Disassembly and Recycling
in the Construction Industry
Dirk SCHWEDE, Elke STÖRL
Institute for Lightweight Structures and Conceptual Design, University of Stuttgart, Stuttgart, Germany,

2. Objectives
The global construction sector is contributing significantly to the global resource consumption. That is why the European Building Products Guideline requires since 2011 that buildings, their materials and parts of the building can be recycled.
At this point in time however the design and building praxis has not nearly achieved this objective. Building structures are in general not designed and constructed for later disassembly and recycling.
Whether a building can be recycled or not, does not only depend on the selection of materials, but also on the joints and connections between the material layers and the building elements. If for instance materials can be separated in specific material groups or if connected materials do not compromise each other in quality, recycling is possible.
The connection technology is not considered sufficiently in many disciplines when buildings are designed and constructed.
In this paper a constructive language is introduced and based on this, design methods and tools for the design are developed. The language is underlaid with databases of information on material, characteristics of joints and the compatibility of materials. The developed approach will support designers to optimize structures and building elements for deconstruction and recycling.

3. Objectives Tool supports the designer to assess:
structure  ability to be deconstructed
jointing principles  ability to be disassembled
materials  recyclability (re-use, disposal)
Tool supports the designer to substitute and improve:
joints with low destruction potential
 joints with high disassembly potential
material layer compromises recyclability of adjacent layer
 neutral material
 joints that allow separation of the layers without contamination

4. Methods
Evaluation of the ability to disassemble joints (DIN , section 3, table 1):
“A connection produced through a joining principle and able to be disassembled, can be undone without destruction of the fitted components.”
“A connection produced through a joining principle and not able to be disassembled can only be undone with damage or destruction of the fitted components.”

5. Methods
Evaluation of the ability to disassemble joints (DIN , section 3, table 2):
5: best performance, 1: weakest performance
5: “able to be undone without damage of the components“
4: “in general able to be undone without damage or destruction of the components”
3: “in general mostly only able to be undone with damage of the components”
2: “in general only able to be undone with damage or destruction of the components”
1: “only able to be undone with damage or destruction of the components”

6. Methods
Evaluation of the ability to disassemble for each fastening principle “joining” (DIN 8580, DIN ):
4.1
Zusammensetzen
4.1.1
Auflegen, Aufsetzen, Schichten
SK, FS 1
4.1.2
Einlegen, Einsetzen SK
4.1.4
Einhängen
SK, FK
4.3
An- und Einpressen
4.3.1
Schrauben KS 2
4.3.4
Fügen durch Presspassung 3
4.3.5
Nageln, Verstiften, Einschlagen 4
4.4
Fügen durch Urformen
4.4.1
Ausgießen FS
4.5
Fügen durch Umformen
4.5.3
Fügen durch Nietverfahren FS 4
4.6
Fügen durch Schweißen
4.6.2
Schmelzverbindungs-schweißen SV 5
4.8
Kleben
4.8.2
Kleben mit chemisch abbindenden Klebstoffen (Reaktionsklebstoffe) AD
5.1
Beschichten
5.1.2
Anstreichen, Lackieren
5.1.4
Putzen, Verputzen

7. Methods
Potential contamination of one matter by another matter (paint, glue, mortar, plaster, etc.) for each material combination: - material contaminates neighbouring material + material is contaminated by neighbouring material = no contamination

8. Methods Elements of the Recycling Graph: boxes: materials
ellipses: coatings
circles: joints, fastenings
Types of fastening:
manufacturing process according to DIN 8580, main group 4 (joining) + 5 (coating)
material
coating
joints, fastenings
type of fastening
DIN 8580
potential contamination
mat.1/mat.2
labelled according to DIN 8580

9. Results External wall with thermal insulation
manufacturing techniques according to DIN 8580
composition (4.3.5 nailing, doweling, driving): non-positive connection
composition (4.4.2 embedding): positive connection
composition (4.8.1 gluing, physical bonding): adhesion
coating (5.1.2 paining, varnishing): adhesion
coating (5.2.1 filling): adhesion
coating (5.3.1 plastering): adhesion
wall composition (from inside to outside) –
classification of materials according to ÖKOBAUDAT
interior paint (dispersion paint)
gypsum surfaces
/.02 concrete
bonding mortar
EPS insulation
plastic dowel
basecoat mortar
reinforcement fabric (glass fibre)
basecoat mortar
base coat
silicone raisin plaster

10. Results
Insulated and ventilated outside wall with curtain brick sheeting on substructure
wall composition (from inside to outside) –
classification of materials according to ÖKOBAUDAT
interior paint (dispersion paint)
gypsum board
Air layer, 30mm
wood slat
screw with dowel
1.4.01/.02 concrete
insulation layer (mineral wool)
thermal spacer PVC (hard)
aluminium wall fastener
vertical aluminium profile
aluminium profile
aluminium clip fastener
air layer, 30mm
aluminium jointing profile
brick sheeting
manufacturing techniques according to DIN 8580
composition (4.1.1 composing, layering): gravity (+friction)
composition (4.1.2 inserting): gravity (+friction)
composition (4.1.4 hinging): gravity, spring power
composition (4.3.1 screwing): non-positive connection
composition (4.4.2 embedding): positive connection
coating (5.1.2 paining, varnishing): adhesion

11. Results Concept visualisation of the RecyclingGraph modelling tool
description of the material and its ability to be recycled
characteristic of the composition technique between material layers
compatibility of two materials and the composition between them

12. Results
ILEK RecyclingGraph Editor

13. Results External wall with thermal insulation RecyclingGraph
ConnectionMatrix
M1 interior paint (dispersion paint)
M2 gypsum surfaces, 3mm
M3 concrete, 180mm
M4 bonding mortar, 5mm
M5 EPS insulation, 140mm
M6 basecoat mortar, 2mm
M7 reinforcement fabric (glass fibre)
M8 basecoat mortar, 3mm
M9 basecoat
M10 silicone raisin plaster, 3mm
M11 reinforcement steel mesh
M12 plastic dowel, 200mm, 60mm
M13 EPS insulation for plastic dowel, 15mm
Structural composition
M2 gypsum board, 12mm
M3 aluminium profile, 30mm x 50mm
M4 concrete, 180mm
M5 thermal spacer PVC (hard), 5mm
M6 aluminium wall fastener, 120mm x 160mm
M7 rivet, steel
M8 vertical aluminium profile, 50mm x 50mm
M9 rivet, steel
M10 aluminium profile, 20mm x 50mm
M11 aluminium clip fastener, 20mm x 50mm
M12 brick sheeting, 390mm x 190mm
M13 air layer, 30mm
M14 reinforcement steel mesh
M15 insulation layer (mineral wool), 140mm
M16 air layer, 30mm
M17 screw, steel
M18 dowel, plastic
M19 dowel, plastic
M20 screw, steel
M21 aluminium jointing profile, 30mm x 60mm
Insulated and ventilated outside wall with curtain brick sheeting on a substructure

14. Results Insulated an ventilated two-shelled brickwork outside wall
RecyclingGraph
ConnectionMatrix
M1 interior paint (dispersion paint)
M2 interior plaster, lime cement, 15mm
M3 vertically perforated brick, 373x175x238mm
M4 insulation layer (mineral wool), 140mm
M5 wind barrier, PE, vapour permeable
M6 air layer, 40mm
M7 clinker brick, 240x115x71mm
M8 mortar, d=12mm
M9 wall tie, l=340mm, 4mm
M10 mortar, d=12mm
M11 clamping disk (fastening of insulation), 50mm
Structural composition
Insulated and ventilated outside wooden post-and-beam wall
M2 gypsum board, 12,5mm
M3 gypsum board, 12,5mm
M4 wood slat, 100mm
M5 oriented strand board, 18mm
M6 screw, steel
M7 wood slat, 180mm
M8 screw, steel
M9 wood slat, 100mm
M10 staples, steel
M11 PP non-woven fabric , sealant
M12 wood slat, 50mm
M13 screw, steel
M14 lumber, larch, 25mm
M15 insulation layer (mineral wool), 100mm
M16 insulation layer (mineral wool), 180mm
M17 insulation layer (mineral wool), 100mm
M18 air layer, 50mm
M19 screw, steel
M20 screw, steel
M21 screw, steel

15. Results Calculation of the primary energy content for the construction
of four typical outside wall structures (life-cycle-elements A1-A3)
PENR: Non-renewable primary energy content
Primary energy content (non-renewable, A1-A3) [MJ/m²]
External wall with thermal insulation
Insulated and ventilated outside wall with curtain brick sheeting on a substructure
Insulated and ventilated two- shelled brickwork outside wall
Insulated and ventilated outside wooden post-and-beam wall
Primary energy content (total, A1-A3) [MJ/m²]
PET: Total primary energy content
External wall with thermal insulation
Insulated and ventilated outside wall with curtain brick sheeting on a substructure
Insulated and ventilated two- shelled brickwork outside wall
Insulated and ventilated outside wooden post-and-beam wall

16. Results
Classification of the recyclability of the structure and the material connections
disassembly [1…5]
compatibility [1…5]
able to be undone without damage of the components
only able to be undone with damage or destruction of the components
compatible
incompatible
compatibility of materials
- poor separability
- poor recyclability
+ good separability
- separated recycling
+ collective recycling
transformable
modular
disassembly [1…5]
external wall with thermal insulation
compatibility [1…5]
insulated and ventilated outside wall with curtain brick sheeting
on a substructure
disassembly [1…5]
compatibility [1…5]
insulated and ventilated two- shelled brickwork outside wall
disassembly [1…5]
compatibility [1…5]
Insulated and ventilated outside wooden post- and-beam wall
disassembly [1…5]
compatibility [1…5]
Classification of the recyclability of the structure and the material connections after the ability to be disassembled and the comptability for processing of the material pairs

17. Acknowledgement
The investigation has been conducted in the context of the Robert Bosch Juniorprofessur “Nachhaltiges Bauen” at the Institute for Lightweight Structure and Conceptual Design (ILEK) at the University of Stuttgart and has been supported by the Robert Bosch Foundation.